Debugging a patch?

Anyone know of a good resource for patch debugging tips? I'm producing a patch that will be applied to around 30 file sets, each a little different. I know it won't work on every one but I need to adjust the diff so that it works as well as it can.

I've been playing with various context lengths and patch fuzz settings with some success, but it's still failing in places I think it should succeed. Google wasn't much help, due to the massive number of disparate hits 'diff' and 'patch' produce. Has anyone been here before and returned to tell the tale?

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